Two index groups (N equals 25, each) of schizophrenics and affective psychotics, a third group of age-matched nonpsychiatric patients (N equals 50), plus three groups (N equals 50, each) of 1st degree relatives of these patients will be screened through a tape-recorded structured interview and their relatives will also be interviewed, using a different interview schedule. Each subject will then receive a 1-hour battery of tests concerned with visual tracking and with lateral dominance. Analogous motor and visual-motor tracking tasks will also be included. The visual tracking target will be a CRT spot moving horizontally at 3 different velocities and produced by waveforms requiring smooth pursuit (sinewaves) or saccadic tracking (squarewaves). Laterality measures will include tests of hand and eye dominance. Tracking performance will be monitored by electro-oculogram (EOG) and the target and EOG waveforms recorded on analog (FM) tape for subsequent computer analysis of waveform distortion, phase lag and cycle by cycle, irregular deviations. The aim is to replicate and extend earlier work which suggests that tracking dysfunction in schizophrenics may be in smooth-pursuit eye movements (only) while saccadic movement, a separate occulomotor mechanism, may be disturbed in the affective psychoses. Since cerebral control centers for saccadic and smooth-pursuit movements are in opposite hemispheres, the issue of cerebral dominance or mixed dominance seems also to be implicated. We have developed tracking tasks, including motor analogs and attention-engaging procedures, as well as improved methods of analyzing quantifying tracking dysfunction, with which we hope to establish with some certitude whether these tracking disorders can in fact serve as sub-clinical indicators of genetic vulnerability to either or both of these psychotic illnesses.